This section provides background information related to the present disclosure which is not necessarily prior art.
Such hydraulic systems are generally known and are used, for example, in motor vehicles for the actuation of a friction clutch (e.g. of a transfer case).
A problem generally exists in such systems of a temperature-induced and/or age-induced zero point migration of the pressure sensor, also called offset drift, which results in a falsification of the measured results supplied by the pressure sensor.
For the first calibration or for the recalibration of the pressure sensor, a pressureless state of the hydraulic system is usually established in that an air bleed valve which separates the hydraulic system from the environment is opened so that the hydraulic system can be set to the environmental pressure. The pressureless state of the hydraulic system (i.e., the status of the hydraulic system at environmental pressure) is then used for the calibration of the pressure sensor (i.e., for the compensation of the sensor offset). The provision of such an air bleed valve means an unwanted apparatus and economic effort.